Life, no principle which limits, 142-143; shortening of, by unhygienic modes of living, 155. Life Extension Institute, purpose of, 1. Lighting, electric preferable to gas, 13. Lime, deficiency of flesh foods in, 39. Linen, use of, in clothing, 17. Literature, avoidance of morbid, 99. Liver, excess of acids produced by eating, 39; among the worst foods, 48. Liver diseases, death rate from, 285. London, expectation of life in, 289. Lusk, Graham, quoted on minimal cost of food, 190-194; experiments by, to ascertain basal metabolism of body, 196. Malaria, not caused by night air, 22; carried by mosquitoes, 71. Marriage, effect of health on opportunities for, 2; exercising wisdom of choice in, 165-166; enactment of wise laws of, 167; science of eugenics and, 293-323. Mastication, required by hard foods, 41; value of thorough, and evils of insufficient, 44-47; a desirable means of tooth and gum hygiene, 84; and mental attitude, 110; experiment to test effects of, on endurance and strength, 200-209. Meat, decrease in amount eaten in middle life and in hot weather, 33-34; high-protein value of, 38; too much, a common error of diet, 38-39; excess of acids produced by, 39; endurance tests to ascertain value of, in diet, 197-199; sudden and complete exclusion from diet not desirable, 208; indulgence of craving for, 209. Meats, table of food values of cooked, 178. Mechanical diet indicator, 202. Medical examination, desirable for determining one's diet, 50. Medical practise, modern radical revolution in, 2-3. Medieval indifference to matters pertaining to human body, 1-2. Melancholy, physical sources of, 57, 105-106. Mendel, discovery of laws of heredity by, 295. Menstrual period in women, mental effects of, 106. Mental condition, relation of mode of breathing to, 26-27; effect on sleep, 104-105; learning to avoid abnormal, 113. Milk, food value of, 30, 181; protein value of human, 37; vitamins supplied by raw, 42; not cooked by pasteurization, 42-43; among the best foods, 48; pasteurizing, for avoiding typhoid germs, 73; skim milk a cheap source of protein, 131. Mind, exercise of the, 97; activity and rest needed by, 105; serenity of, an important factor, 105; interrelation of health and, 105-118. Mind-cure, proper and improper employment of, 111-112. Mineral oils, as intestinal lubricants, 53. Mineral waters, not to be used habitually, 53. Minor ailments, as warning signals, 138-139. Moistening of air, methods for, 12. Monotony and interruption, 92. Moore, R. M., quoted on mortality among abstainers and non-abstainers, 229. Mortality. _See_ Death rate. Mosquitoes, diseases communicated by, 22, 71; preventive measures against, 71-72. Mouth, infection through the, 78-83; preventive measures against infection through, 83-88.